Process for preparing ethylene interpolymers and ethylene interpolymers

ABSTRACT

There is described a novel process for preparing interpolymers comprising ethylene, at least one monomer unit selected from heteroatom substituted olefin monomer units derived from a compound of the formula XV                    
     wherein E and G represent the same or different heteroatoms selected from oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, a hydrocarbyl group, or a substituted hydrocarbyl group, or are joined by a linking group; and n is 0 or an integer from 1-20; or 2,3-dihydrofuran, and optionally carbon monoxide, and interpolymers prepared thereby, including novel interpolymers having melting peak temperatures (T m ) equal to or greater than 50° C.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims benefit to U.S. Ser.No. 09/679,999 filed Oct. 5, 2000.

FIELD OF THE INVENTION

This invention relates to a process for preparing interpolymers ofethylene, at least one or more heteroatom substituted olefin monomers,and optionally carbon monoxide. The process is a high pressure, freeradical initiator, polymerization process. The invention also relates tonovel ethylene interpolymers having T_(m) values of at least 50° C.

BACKGROUND OF THE INVENTION

Plastics and elastomers derived from olefins are used in numerousdiverse applications, from trash bags to fibers for clothing. Olefinpolymers are used, for instance, in injection or compression moldingapplications, such as extruded films of sheeting, as extrusion coatingson paper, such as photographic paper and thermal and digital recordingpaper, and the like. Constant improvements in catalysts have made itpossible to better control polymerization processes, and thus influencethe properties of the bulk material. Increasingly, efforts are beingmade to tune the physical properties of plastics for lightness,strength, resistance to corrosion, permeability, optical properties, andthe like, for particular uses. In addition to chain length andbranching, the incorporation of monomers containing functional groups,such as ethers and esters, offers an opportunity to further modify andcontrol the properties of the bulk material. For example, the earlytransition metal catalyst systems (i.e., Group IV) tend to be intolerantto such functional groups, which often causes catalyst deactivation.

Conventional low density polyethylenes are readily prepared in hightemperature, high pressure polymerizations using peroxide initiators.

These high pressure free radical systems can also be used to prepareethylene copolymers containing functional vinyl monomers, but it isimportant to note that only a small number of monomers can bepolymerized in this high energy (e.g., 200° C., 30K psi) process, i.e.,vinyl acetate and methyl acrylate.

Certain transition metal catalysts, such as those based on titaniumcompounds (e.g., TiCl₃ or TiCl₄) in combination with organoaluminumcocatalysts, are used to make high density polyethylene and linear lowdensity polyethylenes (HDPE ,nd LLDPE, respectively), as well aspoly-α-olefins such as polypropylene. These so-called “Ziegler-Natta”catalysts are quite sensitive to oxygen, sulfur and Bronsted acids, andthus generally cannot be used to make olefin copolymers with functionalvinyl monomers having oxygen, sulfur, or Bronsted acids as functionalgroups.

Zielger-Natta and metallocene catalyst systems, however, have thedrawback that they cannot generally be used in olefin polymerizationreactions with functionalized monomers. It is known in the art thathomogeneous single site transition metal catalysts generally allow forspecific control of catalyst activity through variation of theelectronic and steric nature of the ligand. Homogeneous catalysts areknown to offer several advantages over heterogeneous catalysts, such asdecreased mass transport limitations, improved heat removal, andnarrower molecular weight distributions.

None of the references described above disclose the copolymerization ofolefins with 3,4-epoxy-1 -butene (hereinafter “epoxybutene”),epoxybutene derivatives, and analogs thereof. Epoxybutene is a readilyavailable compound containing two reactive groups: a double bond and anepoxide. By reaction at one or both groups, epoxybutene can easily beconverted into a host of compounds.

The preparation of epoxybutene and derivatives thereof, and examples ofthe same, have previously been described in numerous references,including, but not limited to, U.S. Pat. Nos. 4,897,498; 5,082,956;5,250,743; 5,315,019; 5,406,007; 5,466,832; 5,536,851; and 5,591,874which are incorporated herein by reference. Reaction at one or both ofthese sites affords a host of olefinic derivatives, many of whichcontain versatile functional groups. Polymerization of epoxybutene hasbeen performed using traditional thermal and free radical initiatedreactions, however the pendant epoxide group often does not survive thereaction conditions.

Advances in the polymerization of epoxybutene and its derivativesinclude the following:

L. Schmerling et al., U.S. Pat. No. 2,570,601 describes the thermalhomopolymerization of epoxybutene and the thermal copolymerization ofepoxybutene and various vinyl monomers, such as vinyl chloride, vinylacetate, acrylonitrile, butadiene and styrene.

Polymerization reactions of epoxybutene, in which the epoxide ring isopened to afford polyethers, are known, such as those described in: S.N. Falling et al., U.S. Pat. No. 5,608,034 (1997); J. C. Matayabas, Jr.,S. N. Falling, U.S. Pat. No. 5,536,882 (1996); J. C. Matayabas, Jr. etal., U.S. Pat. No. 5,502,137 (1996); J. C. Matayabas, Jr., U.S. Pat. No.5,434,314 (1995); J. C. Matayabas, Jr., U.S. Pat. No. 5,466,759 (1995);and J. C. Matayabas, Jr., U.S. Pat. No. 5,393,867 (1995).

W. E. Bissinger et al., J. Am. Chem. Soc., 1947, 69, 2955 describes thebenzoyl peroxide initiated free radical polymerization of vinyl ethylenecarbonate, a derivative of epoxybutene.

Cationic polymerization of vinyl ethers (such as 2,3-dihydrofuran) isknown using Lewis acids or proton-containing acids as initiators. Thesemonomers have been shown to polymerize violently through a cationicpolymerization mechanism—often at rates orders of magnitude faster thananionic, or free radical polymerizations—in the presence of bothBronsted and Lewis acids (P. Rempp and E. W. Merrill, “PolymerSynthesis,” Huthig & Wepf, 2^(nd) ed, Basel (1991), pp. 144-152). Olefinaddition polymerization of vinyl ethers via a transition metal mediatedinsertion mechanism has not been demonstrated.

In addition, the synthesis of alternating copolymers and terpolymers ofolefins and carbon monoxide is of high technical and commercialinterest. New polymer compositions, as well as new processes to makepolymers derived from olefins and carbon monoxide, are constantly beingsought. Perfectly alternating copolymers of α-olefins and carbonmonoxide can be produced using bidentate phosphine ligated Pd(II)catalyst systems (Drent et al., J. Organomet. Chem., 1991, 417, 235).These semi-crystalline copolymers are used in a wide variety ofapplications including fiber and molded part applications. Thesematerials are high performance polymers having high barrier andstrength, as well as good thermal and chemical stability.

Alternating copolymerization of olefins and CO using Pd(II) catalystshas been demonstrated by Sen et al., J. Am. Chem. Soc., 1982, 104, 3520;and Organometallics, 1984, 3, 866, which described the use ofmonodentate phosphines in combination with Pd(NCMe)₄ (BF₄)₂ for the insitu generation of active catalysts for olefin/CO copolymerization.However, these catalyst systems suffer from poor activities and producelow molecular weight polymers. Subsequent to Sen's early work, Drent andcoworkers at Shell described the highly efficient alternatingcopolymerization of olefins and carbon monoxide using bisphosphinechelated Pd(II) catalysts. Representative patents and publicationsinclude: U.S. Pat. No. 4,904,744 (1990); J. Organomet. Chem., 1991, 417,235; and U.S. Pat. No. 4,970,294 (1990).

Recent advances in olefin/CO copolymerization catalysis include thefollowing:

Brookhart et al., J. Am. Chem. Soc., 1992, 114, 5894, described thealternating copolymerization of olefins and carbon monoxide with Pd(II)cations ligated with 2,2-bipyridine and 1,10-phenanthroline;

Brookhart et al., J. Am. Chem. Soc., 1994, 116, 3641, described thepreparation of a highly isotactic styrene/CO alternating copolymer usingC₂-symmetric Pd(II) bisoxazoline catalysts;

Nozaki et al, J. Am. Chem. Soc., 1995, 117, 991 1, described theenantioselective alternating copolymerization of propylene and carbonmonoxide using a chiral phosphine-phosphite Pd(II) complex.

None of these references teach the copolymerization of olefins withcarbon monoxide and functionalized olefins, like epoxybutene and relatedcompounds.

U.S. Pat. No. 6,090,900 discloses homopolymers of olefin monomers havingpolar functional groups, and copolymers of these monomers With eachother and With non-polar olefins, and optionally carbon monoxide.

SUMMARY OF THE INVENTION

The present invention is directed to interpolymers comprising ethylene,at least one, or more, monomer units selected from heteroatomsubstituted olefin monomer units derived from a compound of the formulaXV.

wherein E and G represent the same or different heteroatoms selectedfrom oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, ahydrocarbyl group, or a substituted hydrocarbyl group, or are joined bya linking group; and n is 0 or an integer from 1-20; or2,3-dihydrofuran, and optionally carbon monoxide. The novel products ofthe present invention are the interpolymers as described herein that arecharacterized by having a melting peak temperature (T_(m)), asdetermined by the procedure specified herein, of equal to or greaterthan 50° C., preferably from equal to or greater than 50° C. to about115° C.

The novel process for preparing the interpolymers comprising ethylene,the at least one or more monomer unit selected from the specifiedheteroatom substituted olefin monomer unit or 2,3-dihydrofuran, and,optionally, carbon monoxide, including the novel interpolymers of thepresent invention characterized by having a melting peak temperature(T_(m)) of equal to or greater than 50° C., preferably from equal to orgreater than 50° C. to about 115° C., is comprised as follows. Theinterpolymers are produced by polymerization of the monomers in anysuitable high pressure reactor known for the polymerization ofethylene-containing monomer mixtures, examples of which includeautoclaves, tubular reactors and the like. In general, theinterpolymerization of the monomers is conducted at a temperature offrom about 150° C. to about 350° C., at a pressure of from about 68 toabout 304 MPa's (about 671 to about 3000 atmospheres), and for a periodof time of from about 2 to about 600 seconds. The interpolymerizationprocess is conducted in the presence of at least one, or more, freeradical initiators, that are defined as chemical substances that, underthe polymerization conditions utilized, initiate chemical reactions byproducing free radicals.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to interpolymers comprising ethylene,at least one, or more, monomer units selected from heteroatomsubstituted olefin monomer units derived from a compound of the formulaXV

wherein E and G represent the same or different heteroatoms selectedfrom oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, ahydrocarbyl group, or a substituted hydrocarbyl group, or are joined bya linking group; and n is 0 or an integer from 1-20; or2,3-dihydrofuran, and optionally carbon monoxide. The novel products ofthe present invention are the interpolymers as desrcribed herein thatare characterized by having a melting peak temperature (T_(m)), asdetermined by the procedure specified herein, of equal to or greaterthan 50° C., preferably from equal to or greater than 50° C. to about115° C.

The novel process for preparing the interpolymers comprising ethylene,the at least one or more monomer unit selected from the specifiedheteroatom substituted olefin monomer unit or 2,3-dihydrofuran, and,optionally, carbon monoxide, including the novel interpolymers of thepresent invention characterized by having a melting peak temperature(T_(m)) of equal to or greater than 50° C., preferably from equal to orgreater than 50° C. to about 115° C., is comprised as follows. Theinterpolymers are produced by polymerization of the monomers in anysuitable high pressure reactor known for the polymerization ofethylene-containing monomer mixtures, examples of which includeautoclaves, tubular reactors and the like. In general, theinterpolymerization of the monomers is conducted at a temperature offrom about 150° C. to about 350° C., at a pressure of from about 68 toabout 304 MPa's (cabout 671 to about 3000 atmospheres), and for a periodof time of from about 2 to about 600 seconds. The interpolymerizationprocess is conducted in the presence of at least one, or more, freeradical initiators, that are defined as chemical substances that, underthe polymerization conditions utilized, initiate chemical reactions byproducing free radicals.

In more detail, the interpolymers comprise from about 0.1 to about 99.9mol percent (%), preferably about 40 to about 99.9, more preferablyabout 90 to about 99.9 mol %, ethylene; from about 0.1 to about 99.9 molpercent (%), preferably about 0.1 to about 60, more preferably about 0.1to about 10 mol %, of the at least one or more monomer units selectedfrom heteroatom substituted olefin monomer units derived from a compoundof the formula XV

wherein E and G represent the same or different heteroatoms selectedfrom oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, ahydrocarbyl group, or a substituted hydrocarbyl group, or are joined bya linking group; and n is 0 or an integer from 1-20; or2,3-dihydrofuran; and from about 0 to about 10 mol percent (%) carbonmonoxide, all of the amounts based on the total interpolymer.

Exemplary heteroatom substituted olefin monomer units derived from acompound of the formula XV

include the following:

wherein R¹ and R² are independently hydrogen, hydrocarbyl, substitutedhydrocarbyl, heteroatom connected hydrocarbyl, or R¹ and R² collectivelyfrom a bridging group Y wherein Y is hydrocarbyl, substitutedhydrocarbyl, heteroatom connected hydrocarbyl, or heteroatom connectedsubstituted hydrocarbyl; R¹⁰, R¹¹, and R¹² are independently hydrogen,hydrocarbyl, or substituted hydrocarbyl; and Ph is phenyl. Particularlypreferred interpolymers of the present invention include ethylene andeither vinylethylene carbonate, 2,3-dihydrofuran,3,4-diacetoxy-1-butene, and 3-butene-1,2-diol, optionally with carbonmonoxide.

The novel process for preparing the ethylene interpolymers describedherein is further characterized as follows. The interpolymerizationprocess is conducted at a pressure of from about 68 to about 304 MPa's(about 671 to about 3000 atmospheres), preferably from about 103 toabout 241 MPa's (about 1020 to about 2381 atmospheres), and morepreferably from about 138 to about 207 MPa's (about 1361 to about 2041atmospheres). The interpolymerization process is conducted at atemperature of from about 150° C. to about 350° C., preferably fromabout 150° C. to about 250° C., and more preferably from about 150° C.to about 200° C. The interpolymerization process is conducted for aperiod of time ranging from about 2 to about 600 seconds, preferablyfrom about 30 to 300 seconds, and more preferably from about 30 to about60 seconds.

The interpolymerization process is conducted in the presence of at leastone, or more, free radical initiators. As used herein, a free radicalinitiator is defined as a chemical substance that, under thepolymerization conditions utilized, initiates chemical reactions byproducing free radicals. Exemplary free radical initiators, suitable foruse in the present process, include the following listed substances.

1. Organic Peroxides such as

1. Organic Peroxides such as: a t-alkyl peroxyesters such as tert-butylperoxybenzoate, tert-butyl peroxyacetate, tert-butyl peroxypivalate,tert-butyl peroxymaleate, and the like; b. monoperoxycarbonates such asOO-tert-butyl O-isopropyl monoperoxycarbonate, and the like; c.diperoxyketals such as ethyl 3,3-di-(tert-amylperoxy)-butyrate,n-butyl-4,4-di(tertbutylperoxy)-valerate,1,1-di(tert-butylperoxy)-cyclohexane,1,1-di(tert-amylperoxy)-cyclohexane, and the like; d. dialkyl peroxidessuch as 2,5-di(tert-butylperoxy)-2,5-dimethyl-3-hexyne,2,5-di(tert-butylperoxy)-2,5-dimethylhexane, di-tert-amyl peroxide,di-tert-butyl peroxide, dicumyl peroxide, and the like; e. t-alkylhydroperoxides such as tert-butyl hydroperoxide, tert-amylhydroperoxide, α-cumyl hydroperoxide, and the like; f. ketone peroxidessuch as methyl ethyl ketone peroxide, cyclohexanone peroxide,2,4-pentanedione-peroxide, and the like; g. Isobutyryl peroxide,Isopropyl peroxydicarbonate Di-n-butyl peroxydicarbonate, Di-sec-butylperoxydicarbonate, Tert-butyl perneodecanoate, Dioctanoyl peroxide,Didecanoyl peroxide, Diproprionyl peroxide, Didecanoyl peroxide,Dipropionyl peroxide, Dilauroyl peroxide, tert-butyl perisobutyrate,tert-butyl peracetate, tert-butyl per-3,5,5-trimethyl hexanoate, and thelike. 2. Inorganic Peroxides such as Hydrogen peroxide-ferrous sulfate,Hydrogen peroxide-dodecyl mercaptan, Potassium peroxydisulfate, and thelike; 3. Azo Compounds such as2,2′-azobis[4-methoxy-2,4-dimethyl]pentanenitrile,2,3′-azobis[2,4-dimethyl]pentanenitrile, 2,2′-azobis[isobutyronitrile],and the like; 4. Carbon-Carbon Initiators such as2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane,1,1,2,2-tetraphenyl-1,2-bis(trimethylsiloxy)ethane, and the like; 5.Photoinitiators such as Benzophenone, 4-phenylbenzophenone, xanthone,Thioxanthone, 2-chlorothioxanthone, 4,4′-bis(N,N′-dimethylaminobenzophenone (Michler's ketone), benzil, 9,10-phenanthraquinone,9,10-anthraquinone, α,α-dimethyl-α-hydroxyacetophenone,(1-hydroxycyclohexyl)-phenylmethanone, benzoin ethers methyl ethylisobutyl, α,α-dimethoxy-α-phenylacetophenone1-phenyl-1,2-propanedione,2-(O-benzoyl)oxime,diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide,α-dimethylamino-α-ethyl-α-benzyl-3,5-dimethyl-4- morpholinoacetophenone,and the like; Radiation, such as x-rays γ-rays α-particles β-particles

The free radical initiator are generally utilized in amounts of fromabout 1 to about 1000 ppm (parts per million), preferably from about 20to about 300 ppm, and more preferably from about 50 to about 100 ppm,based on the total weight of the ethylene component of the interpolymer.Mixtures of free radical initiators can be used. The free radicalinitiators can be introduced into the polymerization process in anymanner known in the art.

The polymerization process according to the present invention isconducted in a continuous or batch process manner. Any continuous orbatch type process can be used in the practice of the present invention.

The interpolymers of the present invention are useful for one or more ofthe following: printable film; “breathable” film; adhesive formulations;glass-fiber reinforcement; polymer blends; compatibilizing agents;toughening agent for nylon and similar materials; grafting applications;conducting polymers; plastic plating; ionomers; thermosettingapplications; coatings; powder coatings—flame sprayed polyethylene;engineering plastics—impact resistant masses; tie-layers—as thecarbonate or diacetate copolymers or as their hydrolyzed versions, thediols; urethanes; epoxies—through the conversion of the carbonate ringsinto epoxide functionalities; cross-linking agents; moldingapplications; paper and textile additives; low temperature applications;vulcanization; wax applications; clay filled materials for sound barrierapplications; blend components to lower heat seal initiationtemperature; oxygen scavenging applications; as polydiols, for polyesteror polycarbonate synthesis; may be used with typical additives such aspigments, colorants, titanium dioxide, carbon black, antioxidants,stabilizers, slip agents, flame retarding agents, and the like.

The invention will be more readily understood by reference to thefollowing examples. There are, of course, many other forms of thisinvention which will become obvious to one skilled in the art, once theinvention has been fully disclosed, and it will accordingly berecognized that these examples are given for the purpose of illustrationonly, and are not to be construed as limiting the scope of thisinvention in any way. Moreover, all U.S. patents referred to herein areincorporated by reference in their entirety.

EXAMPLES

In the following examples, the test procedures listed below were used inevaluating the analytical properties of the interpolymers.

(a) Molecular Weight Distribution Based on GPC (Mw/Mn)

The Weight Average (Mw) and the Number Average (Mn) molecular weightswere determined using a Waters Gel Permeation Chromatography Series150C/ALC/GPC at 138° C. The method for determining Mw and Mn is thatrecommended by Millipore Corporation, Milford, Mass., in the operatorsmanual 082916TP Revision 0, Oct. 1993. The Gel Permeation Chromatographyunit (GPC) was equipped with ultra styrogel columns and a refractiveindex detector. The instrument automatically calculates the Mw (WeightAverage Molecular Weight) and Mn (Number Average Molecular Weight) usingstandard TriSEC GPC software version 2.70 as sold with the machine. Themachine was calibrated with NBS 1475 polyethylene acquired from the U.S.Department of Commerce National Institute of Standards and Technology inGathersburg, Md. 20899. The solvent used was ortho-dichlorobenzene. Thepolyethylene was dissolved in the orth-dichlorobenzene such that asolution containing 0.1 percent polyethylene was formed. The solutionwas run through the GPC at 1.0 milliliter/minute. Mw and Mn are reportedas grams/mol.

(b) DSC Procedure

Melting Peak Temperature (T_(m)) was determined in accordance with ASTMD 3418-97 using a Differential Scanning Calorimeter (DSC). The T_(m)values listed in the table are not true equilibrium melting points butare DSC peak temperatures of the melt transition recorded on the secondheat cycle. In each case, approximately 10 mg of polymer sample wasplaced in an aluminum sample pan and the sample lid was crimped inplace. The sample was then heated to 150° C. at a rate of 60° C./minuteand held at 150° C. for 5 minutes. The sample was then cooled to 0° C.at a rate of 10° C./minute while recording the freezing orcrystallization curve. After holding for 5 minutes at 0° C., the secondheat cycle was initiated and the sample was heated at a rate of 10°C./minute to a final temperature of 150° C. while recording the heatingcurve. The melting peak temperature, T_(m), was obtained from the melttransition on the heating curve of the second heat cycle. T_(m) valuesare reported as degrees C.

(c) Tg Determination

Tg was determined in accordance with ASTM D3418-82. Tg was measured atthe half height between the base lines drawn from the glassy state andthe rubbery state. The parameters used in this work are the following:Onset and Step Transition Limits are set on “Automatic” mode; StepTransition Midpoint at “Half Height;” Step Signal Change between “Onsetand End.” Tg values are reported as degrees C.

In carrying out Examples 1-8, 13-15, 23, 24, 26 and 27, a batch reactorprocess was utilized. The process involved the use of a reactor set-upconsisting of the following. A 30 mL (milliliter) stainless steel sampletube number 1 (1800 psi rating) was loaded with 30 mL of heptane andpurged with nitrogen gas for 15 minutes. A second 30 mL sample tubenumber 2 (1800 psi rating) was loaded with the designated monomer(s)other than ethylene, peroxide, and an amount of heptane sufficient tobring the total volume of tube number 2 to 30 mL. Upon equilibration ofthe autoclave batch reactor (300 mL, Autoclave Engineers, AE MagnedriveII, Model Number: BC0030SS05AH) to the desired temperature, the contentsof sample tube number 1 were loaded into the reactor followed by thecontents of tube number 2 using ethylene at 306 atm (31 MPa). Thepolymerization was allowed to continue for 2-6 hours. Upon cooling toroom temperature and venting the reactor, the resultant interpolymer wastransferred into an Erlenmeyer flask utilizing acetone as solvent forrinsing the interpolymer mixture out of the reactor. The mixture wasstirred at 400-500 rpm to disperse the interpolymer. 500 mL of methanolwas added to the dispersed interpolymer and the mixture was filtered toisolate the interpolymer. The interpolymer was air dried and subjectedto a vacuum of 1 mm mercury at 45° C. overnight to yield a white powder.

In carrying out Examples 9-12, 16-22, and 25, a continous reactorprocess was utilized. The process involved the use of a high pressurestirred autoclave reactor having a 15 mL capacity. The reactor wassupplied with ethylene at 1800 atm. (182.4 MPa) from high-pressurecompressors, with comonomer(s) other than ethylene, and initiator. Thecomonomer delivery system consisted of a metal casing that housed abalance and a tared, open, metal container with a metal siphoning tubeprotruding into the liquid. The metal casing was pressurized to 4.9 atm.(0.5 MPa) by a membrane pump to provide a suction pressure for efficientcomonomer delivery into the reactor. A digital signal from the comonomerdelivery balance directly to the main control center for the reactorallowed delivery of specified amounts of comonomer into the reactor.Each polymerization reaction was allowed to proceed according to theconditions in Table 1. To avoid air oxidation of exiting hotinterpolymer, a nitrogen gas purging system was installed for eachcollecting, aluminum bin prior to and after collection of sample. To aidin the rapid cooling of the exiting sample, each collecting bin waspartially filled with isododecane. Due to the use of isododecane andincomplete incorporation of comonomer, a work-up was required to isolatepure material. The work-up procedure consisted of grinding interpolymerthat had been cooled with liquid nitrogen, and subjecting the resultingpowder to 1 mm mercury vacuum at 45° C. until a constant weight wasachieved. The polymerization process consisted of the following:Equilibration of temperature of the reactor to a value 30-40 degreebelow the desired working temperature. Equilibration of ethylenepressure was achieved by using two high performance compressors toachieve the approximate required value of 1800 atm. (182.4 MPa). The twocompressors were provided with a required ethylene suction pressure of300 atm. (30 MPa) by a smaller compressor. Upon equilibration ofethylene pressure under the required temperature, initiator wasdelivered into the reactor at one fourth the concentration, and theconcentration was steadily increased to the desired concentration. Thisslow increase in initiator concentration was done in an effort to avoidunexpected “run-away,” or decomposition reactions. The comonomer wasintroduced at the rate and reaction conditions specified in Table 1. Asthe polymerization is an exothermic process, the temperature generallyrose to the desired value during the reaction. Mild external heating wasprovided if this did not occur. The homopolymerization of ethylene wasallowed to proceed for 15-30 min. The comonomer was then injected neator as a solution (30:70 vol/vol) in hexane. Copolymerization was thenallowed to proceed for 30-40 min before collection of interpolymer.

The process of the present invention and interpolymers resultingtherefrom are further described in the following Tables 1 and 2. Table 1includes processing conditions utilized in preparing interpolymers ofExamples 1-27. Table 2 includes the properties of the interpolymers ofExamples 1-27.

TABLE 1 Preparation of Interpolymers of Ethylene with VEC⁴, DAcB⁵,2,3-DHF⁶, or Bu-diol¹⁷ Comonomers Rxn Init Ex. Comon² Pressure TempConc¹⁵ Rxn No.¹ (Concentration)³ Ethylene⁷ Atm/MPa⁸ (° C.)⁹ Init¹⁰ (ppm)Time¹⁶ 1 VEC/3.5 g 0.081 g  31/3.14 100 1⁽¹¹⁾ 92,286 4 hr 2 VEC/15 g0.085 g  68/6.89 200 1 21,533 5 hr 3 VEC/15 g 0.086 g 102/10.3 120 111,400 6.5 hr 4 VEC/5.0 g 1.42 g 170/17.2 80 1 44,000 4 hr 5 VEC/5.0 g1.78 g 204/20.7 90 1 44,000 5 hr 6 VEC/4.4 g 1.78 g 204/20.7 100 150,228 3 hr 7 VEC/5.0 g 1.78 g 204/20.7 110 1 44,000 6.5 hr 8 VEC/10.0 g2.38 g 306/31.0 150 2⁽¹²⁾ 26,000 5 hr 9 VEC/1 g/hr 400 g/hr 1800/182.4200 3⁽¹³⁾ 100 60 sec 10 VEC/3 g/hr 400 g/hr 1800/182.4 200 3 100 60 sec11 VEC/2.6 g/hr 400 g/hr 1800/182.4 240 2 100 60 sec 12 VEC/1.2 g/hr 400g/hr 1800/182.4 240 2 100 60 sec 13 DAcB/2 g 2.38 g 306/31.0 150 226,000 7 hr 14 DAcB/4 g 2.38 g 306/31.0 200 4(¹⁴⁾ 9,000 5 hr 15 DAcB/1 g2.38 g 306/31.0 120 2 26,000 7.7 hr 16 DAcB/5 g/hr 400 g/hr 1800/182.4210 3 100 60 sec 17 DAcB/2 g/hr 400 g/hr 1800/182.4 200 3 50 30 sec 18DAcB/15 g/hr 400 g/hr 1800/182.4 230 3 100 60 sec 19 DAcB/20 g/hr 400g/hr 1800/182.4 230 3 100 60 sec 20 DAcB/30 g/hr 400 g/hr 1800/182.4 2303 100 60 sec 21 DAcB/3 g/hr 400 g/hr 1500/152.0 230 3 100 60 sec 22DAcB/3 g/hr 400 g/hr 1200/121.6 230 3 100 60 sec 23 2,3-DHF/10 g 2.38 g306/31.0 160 4 18,000 4.5 hr 24 2,3-DHF/10 g 2.38 g 306/31.0 150 226,000 4.5 hr 25 2,3-DHF/5.4 g/hr 400 g/hr 1800/182.4 220 2 100 60 sec26 Bu-Diol/1.94 2.38 g 306/31.0 150 2 26,000 4.5 hr 27 Bu-Diol/3.88 2.38g 306/31.0 150 2 26,000 3.5 hr ¹Ex No = Example Number; ²Comon =comonomer; ³Grams of Comonomer for batch reactor or feed rate in g/hrfor continuous reactor; ⁴VEC = vinylethylene carbonate; ⁵DAcB =3,4-diacetoxy-1-butene; ⁶2,3-DHF = 2,3-dihydrofuran; ⁷Grams of ethylenein batch reactor or feed rate into continuous reactor; ⁸EthylenePressure · Atm = atmospheres, MPa = mega pascals, (1 MPa = 1/10⁶pascals); ⁹Rxn Temp = Reaction Temperature in ° C.; ¹⁰Init = initiator;¹¹1 = tert-amyl peroxy-2-ethylhexanoate; ¹²2 = tert-butylperoxy-2-ethylhexyl carbonate; ¹³3 = tert-butyl-per-2-ethylhexanoate;¹⁴4 = tert-butylhydroperoxide; ¹⁵Init Conc = Initiator concentration,ppm = parts per million; ¹⁶Rxn Time = Reaction Time; >60 sec is batchreactor; 60 sec or less is continuous reactor; ¹⁷Bu-diol =3-butene-1,2-diol.

TABLE 2 Properties of Interpolymers of Ethylene with VEC⁴, DAcB⁵,2,3-DHF⁶, or Bu-Diol⁷ Comonomers Example Comon¹/mol %² Tm (° C.) Tg (°C.) Mn (g/mol) Mw (g/mol) Mw/Mn 1 VEC/35 ND³ 37 2,779 4,639 1.67 2VEC/26 ND 110 3,953 5,906 1.49 3 VEC/50 ND 124 6,810 11,564 1.7 4VEC/2.5 110 9,919 54,152 54.6 5 VEC/36 105.7 5,898 11,714 2 6 VEC/29 1006,422 10,647 1.66 7 VEC/47 103 6,217 11,532 11.5 8 VEC/7 89 4,454 6,8011.53 9 VEC/1.1 105 4,454 6,801 1.53 10 VEC/6 80 5,480 27,300 4.98 11VEC/4.3 81 2,700 6,760 3.29 12 VEC/1.7 94 5,290 17,400 3.29 13 DAcB/292.3 2,650 6,050 2.28 14 DAcB/4 78 1,300 2,240 1.72 15 DAcB/1 101.14,240 8,490 2 16 DAcB/1.3 88 7,380 35,100 4.76 17 DAcB/0.3 104 15,40080,900 5.25 18 DAcB/9 ND −37 1,830 4,050 2.21 19 DAcB/12 ND −32 1,6203,290 2.04 20 DAcB/14 ND ND 1,150 1,960 1.7 21 DAcB/1.1 93 4,800 27,3005.69 22 DAcB/3 66 2,940 6,060 2.03 23 2,3-DHF/1 96.2 1,740 2,900 1.67 242,3-DHF/1 103.3 1,450 2,260 1.56 25 2,3-DHF/1 109.7 3,920 10,500 2.68 26Bu-Diol/0.2 107.3 1,480 3,080 1.67 27 Bu-Diol/0.5 105.3 2,640 1,630 1.62¹Comon = comonomer; ²mol % of comonomer - the remainder of the copolymeris ethylene; ³ND = non-determinable, sample is amorphous; ⁴VEC =vinylethylene carbonate; ⁵DAcB = 3,4-diacetoxy-1-butene; ⁶2,3-DHF =2,3-dihydrofuran; ⁷Bu-Diol = 3-butene-1,2-diol.

It should be clearly understood that the forms of the invention hereindescribed are illustrative only and are not intended to limit the scopeof the invention. The present invention includes all modificationsfalling within the scope of the following claims.

We claim:
 1. An interpolymer comprising from about 0.1 to about 99.9 molpercent of ethylene, from 0 to about 10 mol percent of carbon monoxide,and from about 0.1 to about 99.9 mol percent of at least one, monomerunits selected from the group consisting of 2,3-dihydrofuran,vinylethylene carbonate, and 3,4-diacetoxy-1-butene, and saidinterpolymer having a melting peak temperature (T_(m)) equal to orgreater than 50° C.
 2. The interpolymer according to claim 1 wherein theinterpolymer comprises 2,3-dihydrofuran.
 3. The interpolymer accordingto claim 1 wherein the interpolymer comprises from 0.1 to about 99.9 molpercent of ethylene, from 0.1 to about 99.9 mol percent of vinylethylenecarbonate, and zero percent of carbon monoxide.
 4. The interpolymeraccording to claim 1 wherein the interpolymer comprises from 0.1 toabout 99.9 mol percent of ethylene, from 0.1 to about 99.9 mol percentof 3,4-diacetoxy-1-butene, and zero percent of carbon monoxide.
 5. Aninterpolymer having a melting peak temperature (T_(m)) equal to orgreater than 50° C. prepared by the process comprising polymerizing fromabout 0.1 to about 99.9 mol percent of ethylene, from 0 to about 10 molpercent of carbon monoxide, and from about 0.1 to about 99.9 mol percentof at least one, or more, monomer units selected from the groupconsisting of 2,3-dihydrofuran and a heteroatom substituted olefinmonomer unit derived from a compound of the formula XV

wherein E and G represent the same or different heteroatoms selectedfrom oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, ahydrocarbyl group, or a substituted hydrocarbyl group, or are joined bya linking group; and n is 0 or an integer from 1-20, at a temperature offrom about 150° C. to about 350° C., at a pressure of from about 68MPa's to about 304 MPa's, and for a period of from about 2 to about 600seconds, in the presence of at least one, or more free radicalinitiator.
 6. The interpolymer according to claim 5 wherein the monomerunit is a heteroatom substituted olefin monomer unit derived from acompound of the formula XV

wherein E and G represent the same or different heteroatoms selectedfrom oxygen, nitrogen, and sulfur, which are bound to a hydrogen atom, ahydrocarbyl group, or a substituted hydrocarbyl group, or are joined bya linking group; and n is 0 or an integer from 1-20, selected from

wherein R¹ and R² are independently hydrogen, hydrocarbyl, substitutedhydrocarbyl, heteroatom connected hydrocarbyl, or R^(1 and R) ²collectively form a bridging group Y, wherein Y is selected from thegroup consisting of hydrocarbyl, substituted hydrocarbyl, heteroatomconnected hydrocarbyl, or heteroatom connected substituted hydrocarbyl.7. The interpolymer of claim 5 wherein said monomer unit is2,3-dihydrofuran.
 8. The interpolymer of claim 5 wherein said monomerunit is vinylethylene carbonate.
 9. The interpolymer of claim 5 whereinsaid monomer unit is 3,4-diacetoxy-1-butene.
 10. The interpolymer ofclaim 6 wherein said free radical initiator is selected from organicperoxides and inorganic peroxides.